Well-Known Member

So I used a wire brush attachment on a drill to grind down the bottom of my waste tank and applied Flex Seal to retard further erosion. I was pleasantly surprised that under the extreme vacuum of a waste tank it has held up.

So my question is, when I get a new TM, would you recommend that I apply Flex Seal directly to the smooth surface of the bottom of the waste tank or should I use the wire brush attachment to scratch the surface to make the Flex Seal have more grip?

Well-Known Member

I used undercoating that is used for cars when my tank first started to leak from corrosion and it worked for about 1-2 years. I would reseal it about every 6 months but eventually it got too bad to fill in the holes.You got to the clean the bottom as good as possible let it dry for a day and then spray the undercoating on the bottom and then let dry for a couple of days. Pain in the a**. I bought about 4 cans of undercoating and just sprayed it down on the bottom and let it dry. No sanding.

I eventually got tired of that BS and had Jon Don take the tank out. Then I took it to a welding shop and had a new bottom put in. That was about 5 years ago and I have had no problems with it since.